Given that my reflexive response these days to opening a padded mailer and finding yet another urban fantasy inside is a weary sigh, it's always nice to be pleasantly surprised. Blood Engines does what it must to establish its own identity in a crowded urban fantasy marketplace.

Tim Pratt imagines a world in which sorcerers and wizards work behind the scenes to protect us hapless mere mortals from the forces of paranormal nastiness. It sounds like a million such urban fantasy premises, were it not for the fact that Pratt establishes his magical underworld as exactly that, an underworld. Perhaps taking some inspirational cues from the fact, at times in its history, the US government has gotten in bed with some unsavory types in order to get a few rather nasty jobs done, Pratt's magicians seem more like crime lords — even the good ones like Marla Mason. She protects her hometown of Felport with a sidekick, a handful of henchmen, and the ability to ensorcel the mayor and police if need be. And like any kingpin, Marla must always be on the lookout for ambitious and aggressive rivals to her leadership.

It is one of these rivals that sends Marla to San Francisco on a hunt for a rare magical artifact called the Cornerstone. She needs this as it's the only thing to protect her from a hometown rival who is on the verge of cooking up a rather drastic spell that will not merely kill Marla, but erase her — even the memory of her — from the universe entirely. Once in the city by the bay, however, Marla finds herself drawn into a nasty bit of local trouble. All of San Fran's local sorcerers are being assassinated one by one. A renegade mage named Mutex — who sounds, as Marla sardonically notes, like a bad comic book supervillain — needs their blood as well as the Cornerstone in order to work up the magic power necessary to revive an ancient Aztec god. Paranoid and insane in the best possible villain style, Mutex fears the "machinery" of the universe is winding down, and only this deity's revival will stop it.

Pratt has to work a few kinks out of his storytelling before he hits his stride here. He opens the book by throwing us directly into the action. That's good, as he gets the narrative going and doesn't put us to sleep with reams of exposition and long-winded backstory to establish his world. But it also means it's a little hard to warm up to Marla at first, not only because she's all attitude and snark, but she's all attitude and snark in a manner that feels wholly cliché. At least Pratt spares us the snarky and attitude-heavy first-person narration that has become par for the course in urban fantasy. For several chapters, there isn't really a character in Marla for Pratt to develop once he's established her. It isn't until much later in the book — when we finally see, for instance, that there is more to her persona than 24/7 attitude and snark — that she becomes likable and even sympathetic. We can excuse her for being bitchy and stressed out more often than not. After all, someone is trying to erase her from the universe.

As for the book's other characters: Marla's sidekick Rondeau is appealing but not all that exceptional as sidekicks go, though he does do a nice job of reminding us that, at least in Pratt's world, powerful magics do not always trump technology. When a minor god mentions that it will take him two days to reach South America to fulfill a mission for Marla, Rondeau tells him to just take a plane. I also really liked the character of Bowman, a has-been actor (people are forever recognizing him from "that bad sci-fi movie with Dolph Lundgren") with latent psychic powers he'd really rather not have.

Pratt may be a little on-the-nose about name-checking such sources of inspiration as Lovecraft and John Carpenter's Big Trouble in Little China. (As the book opens in Chinatown, Pratt does the latter right in the first chapter, perhaps to ward off criticisms of ripoffery.) There's also an early scene set at a wild Castro sex party — happily nowhere nearly as graphically gross as you might be fearing — that goes on a bit long, probably indicating that Pratt knows a bit more about that subculture than we'd like him to tell us, thanks. But as the book progresses, Pratt, a Bay Area native, makes superb use of San Francisco locations, and the city begins to take on a tactile presence in the story. The book's most ingenious scene takes place on Alcatraz, with Pratt making especially creative use of the concept of alternate universes in addressing a key plot point.

Pratt's just full of ideas here, which you'd think all fantasy writers ought to be good at, but so few actually are. When the book began to offer me Aztec gods and a crazed assassin whose murder weapons of choice are thousands of unimaginably poisonous tree frogs, Pratt officially had my attention. I'm so tired of urban fantasy authors being utterly boring and lazy and giving me nothing but the predictable parade of monsters from the central casting office of Universal Pictures: vampires and werewolves and zombies, oh yawn! A giant frog god who wants to eat the universe? Heads up, people. Now that's a monster. Perhaps Pratt's greatest coup is that he's offered something original, humorous, exciting and fresh in a popular subgenre whose majority of contributing writers can't come up with an idea all their own for love or money. And I'm even including the good ones, like Jim Butcher. Blood Engines earns perhaps the highest accolade a book of this type can attain: it's not like all the rest.